Comparison of screen-detected and interval colorectal cancers in the Bowel Cancer Screening Programme

Abstract

Background:The NHS Bowel Cancer Screening Programme (BCSP) offers biennial faecal occult blood testing (FOBt) followed by colonoscopy after positive results. Colorectal cancers (CRCs) registered with the Northern Colorectal Cancer Audit Group database were cross-referenced with the BCSP database to analyse their screening history.Methods:The CRCs in the screening population between April 2007 and March 2010 were identified and classified into four groups: control (diagnosed before first screening invite), screen-detected, interval (diagnosed between screening rounds after a negative FOBt), and non-uptake (declined screening). Patient demographics, tumour characteristics and survival were compared between groups.Results:In all, 511 out of 1336 (38.2%) CRCs were controls; 825 (61.8%) were in individuals invited for screening of which 322 (39.0%) were screen detected, 311 (37.7%) were in the non-uptake group, and 192 (23.3%) were interval cancers. Compared with the control and interval cancer group, the screen-detected group had a higher proportion of men (P=0.002, P=0.003 respectively), left colon tumours (P=0.007, P=0.003), and superior survival (both P<0.001). There was no difference in demographics, tumour location/stage, or survival between control and interval groups.Conclusion:The FOBt is better at detecting cancers in the left colon and in men. The significant numbers of interval cancers weren't found to have an improved outcome compared with the non-screened population.

Population-based assessment of the outcomes in patients with postcolonoscopy colorectal cancers

“…A population-based study conducted in Manitoba, Canada, found no survival difference between detected and interval cancers 6. In contrast, a study of the UK National Health Service Bowel Cancer Screening Programme that compared screen-detected cancers (based on positive faecal occult blood testing) against non-screen-detected cancers including interval cancers, did find a significant survival difference between the two groups 21. Although a statistical comparison between interval cancers and screen-detected cancers is not specifically reported, the respective survival curves suggest that they may be associated with a worse survival.…”

Screen‐detected and interval colorectal cancers in England: Associations with lifestyle and other factors in women in a large UK prospective cohort

“…UK and other studies of population-based bowel cancer screening programmes [5][6][7][8][9][15][16][17] have consistently reported that interval cancers following negative faecal occult blood screening tests (both gFOBt and faecal immunochemical tests, FIT) tend to be found more often in women, in the right (proximal) colon and rectum, and to be of higher stage than cancers detected by screening; our results for site and stage are consistent with their findings (as is the overall sensitivity of screening). Our results also suggest that cancers of rarer morphologies (mucinous, signet ring cell, neuroendocrine and squamous) are more likely to be detected as interval cancers.…”

“…Some features of screen-detected and interval colorectal cancers have been reported from England 6,7 and from the similar screening programme in Scotland, 5,8,9 but the screening programmes collect only limited information on individual participant characteristics which may be related to cancer detection. Using data from the NHS Bowel Cancer Screening Programme with electronic linkage to an on-going large UK prospective cohort, the Million Women Study, we report here tumour characteristics, including stage, grade, location and morphology, and relationship with lifestyle and other personal factors, for colorectal cancers detected at screening and in the interval between screens among 630,000 women screened in England between 2006 and 2012.…”

A comparison of tumour and host prognostic factors in screen‐detected vs nonscreen‐detected colorectal cancer: a contemporaneous study

“…In assessing the efficacy of colorectal cancer screening, previous work has examined differences between screen-detected and nonscreen-detected disease and has shown improved survival in patients with screendetected disease [21][22][23][24][25][26][27]. Such analysis has, however, focused on the stage and site of tumours, and only one such study has included detailed analysis of adverse tumour factors beyond TNM stage that are of independent prognostic significance [21].…”